Valentine's Raspberry Velvet Tart

For Crust:

1. Mix flour and sugar. Cut in the butter until mixture resembles coarse meal.
    
2. Beat together the egg yolk and whipping cream and pour over flour mixture.
    
3. Stir dough, adding just enough of the water to make a dough.
    
4. Form a ball and flatten into a disk. Wrap in plastic and refrigerate 30 minutes.
    
5. On a lightly floured surface, roll out dough into a 1/8 inch thick round.
    
6. Transfer to a 9 inch tart pan with removable bottom.
    
7. Preheat oven to 350 degrees F.
    
8. Fit dough into bottom and up sides of pan.
    
9. Prick crust all over and cover edges with foil (remove during last 5 minutes of baking).
    
10. Bake crust in at 350 degrees F for 30 minutes, or until golden brown. Cool completely on wire rack.

For Filling:

1. Melt chocolate in the top of a double boiler over simmering water, stirring until smooth.
    
2. Mix in cream and butter. Remove from water.
    
3. Sprinkle raspberries over bottom of prepared crust, saving a few berries for garnish.
    
4. Pour filling over berries and refrigerate until firm, about 1 hour (this can be prepared 1 day ahead and refrigerated, but allow tart to stand at room temperature one hour before serving).
    
5. Garnish with reserved berries and sift powdered sugar over top.